What am I missing streaming music with a Node 2i

That seems like a question only you can answer.  Is it meeting your streaming needs?  Are you happy with the way it sounds?

I have a Node 2 in my main system and am running it through my Auralic Vega DAC and the sound quality is better than using the internal DAC in the Node 2.  The Node 2 is not bad by any means though.  I have one in my bedroom and am running it directly to my preamp using the Node 2's DAC and it sounds very good.  I plan to add an external DAC at some point, but there's no rush on my part to do so. 

Supposedly the 2i sounds better than the Node 2, so you're probably not "missing" anything.

I agree with big greg, if you want higher fidelity, you can always get a better DAC.
I use my Node's solely for wireless connectivity between my office and LR.
B

I added an RME ADI-2 DAC to my Blusound. The SQ went up a few notches. The DAC in the Bluesound is okay but you'll get more w/a quality outboard DAC.

So what’s a good DAC to pair with it? To answer the question about streaming, so far I’ve been building playlists and saving albums on Tidal and have been listening to some of the Blues radio stations on the Node. I just took delivery on a set of Double Impact towers with a center.  Anything that starts that many fights had to find it’s way into my system. I like the sound and they should get better with time. My preamp has a HT bypass so my 2 channel is also part of a 5.0. 

I have been told by a dealer that the DAC's in the Node 2 and Node 2i are the same. The units, in reality, should sound identical.